Via janestreet.com
The quantitative trading giant lost roughly $15 billion in a single month, its worst ever, yet still leads the industry in year-to-date revenue.
Jane Street, the New York-based quantitative trading powerhouse, had a very bad July. The firm lost approximately $15 billion in a single month, its largest monthly loss on record and its first negative trading month since 2016.
What went wrong #
The losses trace back to two primary sources: Jane Street’s exposure to Situational Awareness, the AI-focused hedge fund founded by Leopold Aschenbrenner, and a broader set of misguided bets in Asian equity markets. When AI-related equities experienced a severe selloff, the firm found itself on the wrong side of a trade that had, until recently, seemed like a consensus winner.
Jane Street had previously invested roughly $2.5 billion in Situational Awareness before the market unwound. Adverse positions in the technology sector compounded the damage.
In an internal memo, partner Turner Batty described July as a “bad month” but was quick to note that the firm’s core short-horizon strategies, the bread-and-butter market-making operations that have fueled its ascent, remained profitable throughout the turbulence.
The bigger picture is still extraordinary #
Despite absorbing a $15 billion hit in July, Jane Street’s year-to-date net trading revenues still exceeded $40 billion through early to mid-August 2026. That figure surpasses the firm’s entire 2025 annual total of $39.6 billion.
Recalibration underway #
In the wake of the July losses, Jane Street is reportedly recalibrating its risk exposure across several business lines. The firm is also working on a debt refinancing strategy designed to strengthen its financial position.
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